It is desirable to generate random numbers or random data for various applications in electronic circuits. One such application is in secure data systems in which a serial stream of random digital bits is generated for creating new encryption keys.
Various methods have been used in the past to generate random numbers. Some of these methods generate essentially true random numbers as, for instance, circuits which amplify the shot noise in a resistor; and some circuits produce pseudo-random numbers using computer algorithms. However, with electronic keys, which tend to be small circuit modules having one or two integrated circuits, there is not a lot of chip area available on which to fabricate a random number generator.
Therefore, it can be appreciated that a random number generator circuit which produces random numbers on a relatively small area of an integrated circuit is highly desirable.